The present invention relates to a splicer for splicing strips of cords embedded in rubber material to each other, which device is provided with a supply transport device for supplying the strips in a supply direction, with a splicing unit for splicing the strips to each other, which splicing unit comprises a splicing table and a splicing machine placed over the splicing table, in which the supply transport device supplies the strips to the splicing unit, and with a discharge transport unit for discharging the strips spliced to each other. The cords embedded in the rubber material may for instance be of steel or the like.
Such splicers are known and have been used for quite a number of years. In said known devices the strips are supplied to the splicing table and are slid over the splicing table until at the splicing position.
For instance, a device is known from U.S. Pat. No. 4,832,780 for connecting strips of cords embedded in rubber material to each other. This device has a supply transport device for supplying the strips to a splicing table. A positioning device over the splicing table positions the strip. The problem here is that the strip may deform during the positioning.
Another device is known from U.S. Pat. No. 3,935,056 for splicing strips of cords embedded in rubber material to each other. Here the strips are supplied to a splicing table divided into halves. The angle of the halves with respect to each other can be adjusted, albeit limited to large angles.
Yet there is a need in the art for a splicer with which the productivity as well as the quality of the strips spliced together is improved.
To that end a splicer of the kind described above according to the invention is characterized in that the supply transport device is provided with a first transport unit and a second transport unit that are in line with each other, in which the first transport unit supplies strips to the second transport unit, in which the second transport unit supplies strips to the splicing unit and has an inlet end and an outlet end, and that the outlet end of the second transport unit and the splicing table are laterally, that means transverse to the transport direction, movable with respect to each other. Indeed because the splicing table and the second transport unit are laterally moveable with respect to each other, can the strip on a laterally adjustable position be supplied to the splicing table.
In a preferred embodiment of a splicer according to the invention the second transport unit is laterally movable in its entirety. Alternatively the second transport unit can be rotatably mounted around its inlet end. Additionally or alternatively the splicing table can be laterally movable in its entirety.
Especially with narrow and/or limp strips the sliding of strips over the splicing table results in inaccurate positioning because of which the splicing together of two strips takes place unreproducibly and insufficiently accurate. Generally the strips have a triangular leading and a triangular trailing tip, and particularly a sharp tip can be pointed upwards unwantedly during the sliding. The known splicers try to limit this effect as much as possible by selecting the point of rotation of the splicing unit, that forms a splice line, at the side of the obtuse angle of the tip. As a result deviations occur at one side of the strips spliced together, which may lead to an unacceptably large deviation. In an embodiment of the splicer according to the invention this is solved because the splicing machine is rotatably mounted, and that the point of rotation is formed by the middle of the splice line. In this way possible deviations are distributed over both sides of the strips and the resulting (halved) deviation may be acceptable indeed.
In order to reduce inaccuracies in the positioning as a result of the sliding of the strips over the splicing table, in an embodiment of a splicer according to the invention the splicing table is provided with a longitudinal axial line dividing the splicing table in a first splicing table half and a second splicing table half, an inlet end, an outlet end, a first splicing table transport unit placed on the first splicing table half, which first splicing table transport unit extends from the inlet end of the splicing table up to a distance from the inlet end of the splicing table, and preferably a second splicing table transport unit placed on the second splicing table half, which second splicing table transport unit extends from the outlet end of the splicing table. As a result half of the supplied strip can be placed on the first splicing table transport unit and for instance by synchronised drive with the second transport unit the strip can be supplied in position on the splicing table without loss of accuracy. Together with the discharge transport device the second splicing table transport unit ensures the discharge of two strips that have been spliced to each other.
In order to transport the strip to a predetermined position on the splicing table it is advantageous that a first sensor is provided for determining the centre of the strip between the first transport unit and the second transport unit and for generating a starting position signal. In this way a strip can be positioned at a very early stage, which increases the accuracy of the splice.
Preferably a second sensor determines the position of the strip between the second transport unit and the splicing table and it also generates a middle position signal, and a third sensor determines the position of the strip under the splice line and it generates an end position signal. As a result last-minute position alterations can be made.
Preferably a computer is provided having a file in which a target position has been included, and a comparer for comparing a position signal generated by one of the sensors and fed into the computer, with the target position and for issuing a control signal for controlling the relative lateral position of the splicing table and/or the second transport unit. In a computer controlled manner the position of the splicing table and/or the second transport unit can thus be set. With the help of the obtained computer data the conveyor belts can be controlled as well. The computer control and sensors form means for controlling the corrections. The corrections are carried out during the supply of the strips, as a result of which a splicer can be obtained having a swift processing of strips.
A very accurate splice is obtained when the target position is the middle of the splice line.
The accuracy of the splice is further improved when the first and second splicing table transport unit and the second transport unit decelerate in a synchronized manner to a speed zero, so that splicing the strips to each other takes place with motionless strips.
In an embodiment the first and second transport units are of a type supporting the strips over almost their entire length. As a result the transport is monitored. To realise a better monitoring of the movement in an embodiment, the transport units are provided with means for retaining the strips on the surface of the transport units. Said means may for instance be suitable for generating magnetic fields or vacuum between the strips and the surface of the transport units. Because of this the supply takes place in a controlled manner. In this embodiment it is preferred when the means for retaining the strips can be switched on and off.